Pressure cookers generally comprise a vat or cooking vessel of a size to receive a wire basket in which the product to be cooked is placed and then immersed in the cooking oil contained in the vat. The vat is closed by a lid which is sealed to the top of the vat, whereupon the product is cooked for the desired length of time under both heat and pressure. Following the cooking cycle, the pressure in the vat is relieved and the lid is opened, whereupon the product is removed from the wire basket.
The type of large capacity pressure cooker to which the present invention is directed is illustrated and described in the above noted co-pending application, the teachings of which are incorporated herein by reference. During the cooking operation, when the vat is pressurized, it is imperative that the vat lid be firmly closed and locked, as a matter of safety.
It will be appreciated that the vat lid and its associated mechanism is large and heavy making it difficult to shift the lid vertically between its open and closed positions. Prior art workers have devised counter balancing mechanisms to alleviate this problem. Nevertheless, the prior art large capacity pressure cookers are characterized by very complex lid opening, closing and leveling means which require considerable operator manipulation of a series of elements. Many of the opening, closing and locking mechanisms are such that it is impractical for the cookers to be operated by personnel lacking the size and physical strength to cope with the rigors of manual operations required to operate the equipment. Some require manipulation of a first handle for raising and lowering the lid, and manipulation of a second handle for locking the lid in its closed position.
In contrast to the foregoing, the present invention provides a large capacity pressure cooker capable of handling, for example, 10 heads of chicken, while at the same time providing a lid opening, closing and locking mechanism which can be operated by the average worker without undue physical exertion and with a minimum of manipulation. The lid opening, closing and locking mechanism is operated by a single handle and is simpler in construction and operation than those of the prior art. In addition, positive means are provided to preclude mistaken unlocking and opening of the vat lid while the vat is pressurized.